Just another ST50 build

[RADFAB]

so does that mean one can use 150 psi say from a shop compressor?

[jetric]

If the shop air compressor can continously supply 150psi through a 5mm diameter hole which most shop air compressors can't unless it's a large screw compressor one because you can't rely on the air tank volume because if the compressor can't keep filling the air tank with sufficient volume of 150psi air then the pressure in the tank will fall.
There's no harm in trying it though but you must make sure that there are no restrictions in the air line smaller than the 5mm nozzle drilled in the comp housing because you need flow and pressure, that's why I use the scuba tank with a short high pressure hose.
I can normally get four starts before the tank needs filling.

Richard S.

Nov 23, 2023 13:43:44 GMT -5 RADFAB said:

so does that mean one can use 150 psi say from a shop compressor?

[racket]

The average workshop air compressor won't work ,as Richard explained it runs out of "pressure" very quickly , its OK for small automotive sized turbo based engines but once you start getting into truck sized units with their higher rotor inertia they aren't up to the job .

When I first started trying to fire up my TV84 turbo based bike engine back in the late 1990s I went through the usual methods starting with the air compressor which was a failure, then I tried using full pressure from my oxy cylinder , it worked but feeding pure oxygen into an engine wasn't the best idea , also it was expensive , so ended up purchasing the trusty leafblower which at first worked marginally as it didn't produce enough "pressure" to force the air through the engine , but once I fitted a shroud onto the comp wheel blades and reduced clearances and losses within the blower it performed as expected , and was was used to start a number of subsequent engine builds , 25 years later it still does a great job of blowing leaves :-)

Cheers
John

[RADFAB]

I know the leaf blower really is all around best choice. John do you happen to have any pictures of those blower mods? Could never have too much blowing when it comes to your blower

[racket]

Theres some pics of a larger backpack blower I fitted a shroud to jetandturbineowners.proboards.com/thread/1459/11-127-manned-flight-engine?page=15 ,

I don't have pics of my original one , heh heh , done before the days of digital cameras .

I also added packing between the outer plastic comp housing wall and the wheel shroud near the inlet to prevent backflow loss of "compressed ??" air , I used layers of "first aid" cloth sticking plaster to get the right clearance.

I tested the blower before and after the mods by using a water manometer to measure blower output pressure , "calibrated??"blocking discs were taped to the outlet of the blower to allow measuring of max pressure by poking the manometer inlet though the disc.

Its important to use a radial blower only type leafblower , blower/vac units have too much clearance inside and aren't designed for pressure production , neither are axial fan leafblowers .

These days there are relatively inexpensive backpack blowers which should start your engine without any mods needing to be done to the blower , they didn't exist 25 years ago, hence the need for the mods I made .

[jetric]

Or you could use a Bosch router with a silicone coupling for a cushioned drive onto the comp nut as I did 24 years ago!
Wow how time flies by!

youtu.be/s67b6D6grUM?si=7uCH9l3a3v8yw30o

Richard S.

Nov 24, 2023 2:29:07 GMT -5 RADFAB said:

I know the leaf blower really is all around best choice. John do you happen to have any pictures of those blower mods? Could never have too much blowing when it comes to your blower

[racket]

Hi Richard

Unfortunately this turbo "runs backwards" :-(

The good old router was the weapon of choice back then when there wasn't much choice for high speed starters ,

LOL................yep the years have disappeared too quickly, and seem to be increasing in speed :-(

Cheers
John

[RADFAB]

Actually I purchased that router I was talking about in the beginning of this thread and was able to change the direction super easy. The coupling was actually the only thing I was perplexed about. What is this silicone coupling I hear of?

[richardm]

Try looking at those couplers they use to start nitro engines onR/C planes
www.amazon.com/Terminator-Aluminum-Starter-20-80CC-Airplane/
dp/B07RW78H5X?th=1

Just an example I don't know what size you need..

But you may need to adapt it to your router and lock it in place if it is screwed on but rotates the wrong way.
You may want to order a few spare silicone cups as they tend to wear out fast

[jetric]

If you can message me your email address then I can send you the pictures with all the details of the coupling. I can't upload any pictures to that imgbb that we use on here, It was better when we were on the yahoo group as it was easy to upload pictures on that and I had all the pictures of all my builds on there but I've deleted them off there now because we don't use it now,

Richard S.

Nov 24, 2023 15:55:00 GMT -5 RADFAB said:

Actually I purchased that router I was talking about in the beginning of this thread and was able to change the direction super easy. The coupling was actually the only thing I was perplexed about. What is this silicone coupling I hear of?

[RADFAB]

Here is the information Richard shared with me on his coupling for starting with a router motor. Thanks again Richard. Now I'll just have to figure out how to work the router while working fuel at same time lol.